Perforating apparatus

ABSTRACT

IN THE REPRESENTATIVE EMBODIMENT OF THE PRESENT INVENTION DISCLOSED HEREIN, SHAPED CHARGES ADAPTED FOR INSTALLATION IN A TYPICAL END-LOADED CARRIER ARE RESPECTIVELY PROVIDED WITH A RIGID ANNULAR RETAINER MEMBER WHICH IS MOVABLY DISPOSED ON THE FORWARD END OF EACH CHARGE. CAMMING SURFACES ARE COOPERATIVELY ARRANGED FOR SHIFTING THE RETAINER MEMBER FORWARDLY IN RELATION TO THE SHAPED CHARGE ONCE IT IS INSTALLED IN THE CARRIER FACING AND ALIGNED WITH A LATERAL PORT THEREIN. IN THIS MANNER, WHEN THE PORT PLUG IS INSTALLED IN THE PORT, IT WILL ENGAGE THE RETAINER AND TIGHTLY ANCHOR THE SHAPED CHARGE IN POSITION.

Feb. 20, 1973 J. B. SHORE PERFORATING APPARATUS Filed June 23, 1971 James 8. Shore IN VE N TOR A TTORNE Y United States Patent Oflice 3,717,207Patented Feb. 20, 1973 ABSTRACT OF THE DISCLOSURE In the representativeembodiment of the present invention disclosed herein, shaped chargesadapted for installation in a typical end-loaded carrier arerespectively provided with a rigid annular retainer member which ismovably disposed on the forward end of each charge. Camming surfaces arecooperatively arranged for shifting the retainer member forwardly inrelation to the shaped charge once it is installed in the carrier facingand aligned with a lateral port therein. In this manner, when the portplug is installed in the port, it will engage the retainer and tightlyanchor the shaped charge in'position. Y

One of the more typical oil field perforators in com.- mon usage todayis comprised of an enclosed tubular body having one or morelaterally-directed shaped explosive charges mounted atlongitudinally-spaced intervals therein and operatively associated withelectricallyresponsive detonating means. As is typical, the perforatorbody or so-called carrier is a heavy-walled cylinder designed towithstand the extreme explosive forces produced by the detonation of theexplosives carried therein. To permit the carrier to be reused, eachshaped charge is respectively faced toward a lateral port in the carrierbody which is customarily covered by an expendable portclosure membersuch as a threaded plug which is fluidly sealed in the port. Thoseskilled in the art will recognize, of course, that for a given carriersize, significantly larger shaped charges can be employed where thecharges can be inserted into one end of the carrier rather than beinginstalled through the lateral ports in the carrier wall.

Many mounting arrangements have, of course, been proposed heretofore forsuch end-loaded carriers to retain the shaped charges accurately alignedwith their associated ports despite the sharp impacts and severeoperating conditions which perforating apparatus customarily encountersduring typical perforating operations. For example, one typical mountingarrangement (as shown in Pat. No. 3,246,707 at 60) employs a metallicapertured cover or a truncated conical sleeve which is secured over theforward end of a shaped charge and adapted for contacting its associatedport plug to firmly secure the shaped charge in position when the portplug is installed into the port opening. Similarly, another commondesign employs a thick resilient sleeve which is coaxially mountedaround the forward end of a shaped charge and adapted to be axiallycompressed between the base of the port plug and the charge case as theplug is tightened.

It has been found, however, that alignment devices such as thesesignificantly impair the formation of the perforating jet which isproduced upon detonation of the shaped charge. In particular, since suchretainers are typically mounted just ahead of the shaped charge linerand must converge forwardly at a steep angle to engage the base of theport plug, these retainers have been found to lie in the path of theliner materials which are driven inwardly and forwardly from the skirtor forward portion of the liner as the liner is collapsed by theexplosive forces developed upon detonation of the shaped charge.Interference of this nature will, of course, substantially affect theoverall performance of the shaped charge.

Accordingly, it is an object of the present invention to provide new andimproved perforating apparatus having one or more shaped explosivecharges which are secured in an enclosed end-loaded carrier in precisealignment with their respectively-associated port-closure memberswithout impairing the operating performance of the shaped charges.

This and other objects of the present invention are attained by movablydisposing annular retainer means on a shaped explosive charge formovement thereon between a first or retracted position permittingplacement of the shaped charge within an enclosed carrier facing alateral port and a second or extended position for abutment with aport-closure member in stalled in the lateral port for tightly securingthe shaped charge in the carrier and in alignment with the port.

The novel features of the present invention are set forth withparticularity in the appended claims. The invention, together withfurther objects and advantages thereof, may be best understood by way ofthe following description of exemplary apparatus employing theprinciples of the invention as illustrated in the accompanying drawings,in which:

FIG. 1 shows typical perforating apparatus employing the principles ofthe present invention;

FIG. 2 depicts a perferred embodiment of the new and impoved perforatingapparatus of the present invention;

FIGS. 3 and 4 are additional views showing the details of the preferredapparatus illustrated in FIG. 2; and

FIGS. 5 and 6 are enlarged cross-sectional views respectivelyillustrating the assembly of the apparatus of FIG. 2.

Turning now to FIG. 1, new and improved perforating apparatus 10incorporating the principles of the present invention is depicted as itwill appear when suspended in a well bore 11 by a typical electricalcable 12. As illustrated, the perforating apparatus 10 includes anelongated tubular body or carrier 13 having a plurality oflongitudinally-spaced side openings or ports 14 which are respectivelyfluidly sealed and closed by a port-closure member such as a threadedplug 15. The perforating apparatus 10 further includes perforating meanswhich, in the preferred embodiment of the present invention, arecomprised of a plurality of laterally-directed shaped explosive charges16 disposed at longitudinally-spaced intervals in the carrier 13 and, aswill subsequently be explained, are secured therein respectively facingthe lateral ports 14. As is typical, the perforating means furtherinclude selectively-operable detonating means such as anelectrically-responsive blasting cap 17 operatively coupled to a lengthof detonating cord 18 that is mounted in detonating proximity of each ofthe shaped charges 16.

As best seen in FIG. 2, in the preferred embodiment of the shapedcharges 16, a typical shaped charge liner 19 is operatively disposed inthe hollowed forward end of an explosive pellet 20 and adapted forproducing, upon detonation, a perforating jet which is directed along aselected perforating axis 21 toward the right as viewed in the drawings.The shaped charge 16 further includes a cylindrical container which inthe illustrated preferred embodiment is comprised of a metallic innerjacket 22 and an outer case 23 of a suitable plastic material forminimizing the effects of laterally-directed explosive forces on theinterior walls of the carrier 13. The rear of the outer case 23 isreduced as illustrated to provide a rearwardly-projectingaxially-aligned boss 24 having a slot or opening 25 for retaining thedetonating cord 18 within detonating proximity of the explosive pellet20. Since the outer case 23 must complementally fit the internalconfiguration of the carrier 13, the forward end of the case is rounded,as at 26, in a plane perpendicular to the plane of the drawings.

To selectively secure the shaped charge 16 in position within thecarrier 13, the preferred embodiment of the present invention includesretaining means, such as a somewhat-hemispherical rigid member 27 havinga central opening 28 formed therein and an annular spacer 29, which arecooperatively arranged to be movably positioned along the axis 21between the case 23 andthe closure plug 15. The present inventionfurther includes camming means which, in the preferred embodiment i1-lustrated in FIG. 2, are provided by a corresponding number ofequally-distributed rearwardly-directed projections or legs on thehemispherical retainer 27 and forwardlyfacing axially-inclinedcamsurfaces 31 disposed around the interior wall of the forward end of thecase 23. It will be appreciated, therefore, that when the legs 30 of theretainer 27 are disposed on the camming surfaces 31, clockwise rotation(as viewed in FIG. 3) of the retainer in relation to the shaped charge16 and about the axis21 will cause the retainer to advance forwardlyalong the axis 21 and relative to the case 23 from an initial rearwardposition to a forward position. The amount of forward or axialadvancement of the retainer 27 in relation to the charge 16 will, ofcourse, be determined by the longitudinal or axial spacing between therearward surfaces 32 and the forward surfaces 33 on opposite ends of thecamming surfaces 31. Shoulders, as at 34, are preferably arranged on theforward surfaces 33 to prevent continued clockwise rotation of theretainer 27 once the legs 30 are engaged on the forward surfaces 33.

Accordingly, it will be recognized from FIGS. 24 that when the legs 30are engaged on the rearward surfaces 32, the retainer 27 will bewithdrawn into the forward end of the case 23; and, by appropriatelydimensioning the several elements of the present invention in relationto the carrier 13, the forward end of the retainer will be at leastsubstantially confined within the forward case end. Conversely, uponclockwise rotation of the retainer 27 in relation to the shaped charge16, the retainer will be advanced forwardly along the axis 21 to asecond or forward position where the forward face of the retainer isprojected at least slightly ahead of the case 23.

Turning now to FIG. 5, the shaped charge 16 is shown positioned in thecarrier 13 adjacent to and facing one of the ports 14 and incoincidental alignment therewith. As illustrated, the internal rear wallof the carrier 13 is provided with an inwardly-facing recess which iscoincidentally aligned with the port 14 and complementally shaped topartially receive the boss 24. The detonating cord 18 is disposed in theopening 25. At this time, the retainer 27 is angularly oriented inrelation to the shaped charge 16 so as to locate the legs 30 on therearward surfaces 32 and thereby retracting the retainer into theforward end of the case 23. This will, of course, allow the shapedcharge 16 to be installed through one end and into the carrier 13 by atypical loading tool (not shown) and held in the illustrated positionuntil the charge is secured into position.

Once the charge 16 is positioned, the retainer 27 is rotated in aclockwise direction by inserting a tool (not shown) into the port 14. Inthe preferred embodiment i1- lustrated, slots or lugs, as at 36, arearranged in the retainer opening 28 for engagement by this tool torotate the retainer 27. Rotation of the retainer 27 will bring the legs30 up the camming surfaces 31 onto the forward surfaces 33 until thelegs contact the stops 34. Then, as illustrated in FIG. 6, the retainerspacer 29 is inserted into the opening 28 and the port plug 15 isthreaded into the port 14 until the base of the plug is engaged with thespacer to firmly seat the boss 24 in the recess 35 and secure the charge16 between the rear wall of the carrier 13 and the base of the portplug. It will be recognized, of course, that the plug 15 is tighteneduntil the legs 30 are tightly engaged against the seating surfaces 33.

Accordingly, it will-be recognized that. the present, invention hasprovided new and improved perforating apparatus in which one or moreshaped charges can be firmly secured in an endloaded carrier andaccurately positioned in coincidental alignment with their respectivelateral ports. Moreover, by virtue of this new=and improved apparatus,undue interference with the perforatingjet is eliminated. Y i

While a particular embodiment of the present invention has been shownand described, it is apparent that changes and modifications may be madewithout departing from this invention in its broader aspects; and,therefore, the aim in the appended claims is to cover all such changesand modifications as fall within the true spirit and scope of thisinvention.

What is claimed is: I

1. Perforating apparatus comprising: a tubular body having a lateralport in a wall thereof providing access to the internal bore thereof;perforating means in said body and including shaped explosive chargemeans transversely oriented, in said internal bore and having itsforward end, facing said port; and means cooperatively securing saidshaped'charge means in coincidental alignment with said port includingrigid retainer means movably disposed between said shaped charge meansand said port, camming means cooperatively arranged between saidretainer means and said shaped charge means and adapted for axiallyshifting said retainer means forwardly in relation to said shaped chargemeans upon rotation of said retainer means from a rearward retainerposition permitting insertion of said transversely-oriented shapedcharge means and said retainer means into said internal bore to aforward retainer position where a forward portion of said retainer meansis advanced ahead of said forward end of said shaped charge means, andmeans adapted for insertion into said port for closing said port andengaging said forward end of said retainer means for securing saidshaped charge means between said retainer means and the opposite wall ofsaid body.

2. The perforating apparatus of claim 1 further including arearwardly-directed portion on said shaped charge means, and a recess insaid opposite wall of said body coincidentally aligned with said portand adapted to at least partially receive said rearWardly-directedportion of said shaped charge means.

3. The perforating apparatus of claim -1 wherein said perforating meansfurther include electrically-responsive detonating means cooperativelyassociated with said shaped charge means and adapted for detonating saidshaped charge means in response to an electrical signal.

4. The perforating apparatus of claim 1 wherein said retainer meansinclude an annular member having a forwardly-curved forward end and arearwardly-directed annular portion coaxially arranged around saidshaped charge means defining a first part of said camming means; andsaid shaped charge means having a forwardly-directed annular portiondefining a second part of said camming means.

5. The perforating apparatus of claim 4 wherein one of said annularportions includes an inclined surface defining one of said first andsaid second parts of said Carnming means and the other of said annularportions includes a cooperative surface defining the other of said firstand second parts of said camming means.

6. The perforating apparatus of claim 4 wherein said rearwardly-dircctedportion of said annular member includes a plurality of outstandinglegsand said forwardly-directed portion of said shaped charge means includesa plurality of axially-inclined surfaces adapted for en- 'gagement bysaid outstanding legs for advancing said annular member upon itsrotation in relation to said shaped charge means.

7. Perforating apparatus comprising: a tubular body adapted forsuspension in a well bore and having at least one laterally-directedthreaded port therein providing access to the internal bore of saidbody; perforating means in said body and including a shaped explosivecharge disposed in a cylindrical case member uniformly arranged aroundthe perforating axis of said shaped explosive charge and having aforward portion projecting forwardly of said shaped explosive charge;and retaining means adapted for securing said shaped explosive chargetransversely in said body facing said threaded port and in coincidentalalignment therewith and including a rigid annular retainer membercoaxially arranged around said perforating axis between said shapedexplosive charge and said threaded port, camming means including firstand second coengaged surfaces cooperatively arranged on said members foraxially advancing said retainer member ahead of said forward caseportion upon rotation of said retainer member, and means including athreaded portclosure member adapted for engagement with said retainermember in its said extended position.

8. The perforating apparatus of claim 7 wherein said retainer member isdisposed within said forward case portion and is movable from aretracted position therein to an extended position upon rotation of saidretainer member.

9. The perforating apparatus of claim *8 wherein said first surfaces arecomprised of a plurality of axially-inclined surfaces distributedcircumferentially around said forward case portion and said secondsurfaces are comprised of a corresponding number ofrearwardly-projecting legs on said retainer member.

10. The perforating apparatus of claim 8 wherein said first surfaces areinclined axially and said second surfaces are transverse to saidperforating axis.

11. The perforating apparatus of claim 10 wherein said first surfacesare on said case member and said second surfaces are on said retainermember.

12. A shaped charge assembly adapted for installation in an enclosedtubular carrier and facing a lateral port in the wall of such a carrier,said assembly comprising: a

cylindrical case having an open forward portion complementally shaped toconform to the internal wall of a tubular carrier and a closed rearwardportion adapted to receive a shaped explosive charge; a shaped explosivecharge disposed in said closed case portion and faced forwardly towardsaid open case portion; an annular retainer member movably disposed onsaid open case portion; and camming means cooperatively arranged betweensaid retainer member and said forward case portion and adapted formoving said retainer member ahead of said forward case portion uponrotation of said retainer member.

13. The assembly of claim 12 wherein said retaindr member is receivedwithin said forward case portion ahead of said shaped explosive charge.

14. The assembly of claim 12 wherein said camming means are comprised offirst surfaces on said forward case portion and second surfaces on saidretainer member cooperatively engaged with said first surfaces andadapted for axially advancing said retainer member forwardly uponrotation of said retainer member.

15. The assembly of claim 14 wherein said retainer member is receivedwithin said forward case portion ahead of said shaped explosive charge.

16. The assembly of claim 14 wherein when said retainer member isrearwardly positioned relative to said forward case portion, saidretainer member is in the path of jet particles emanating from saidshaped explosive charge upon its detonation, and when said retainermemher is positioned forwardly relative to said forward case portionsaid retainer member is out of said jet particle path.

References Cited UNITED STATES PATENTS 2,765,739 10/1956 Mohaupt et al.4.6 2,844,098 7/1958 Castel 1754.6

DAVID H. BROWN, Primary Examiner

